Known in the art is an air cleaner (V. E. Maev, N. N. Ponomarev. "Air-Cleaners for Automobile and Tractor Engines", 1971, "Machinostrojenie" Publishing House, (Moscow), p. 76-77) comprising a cylindrical housing positioned vertically, wherein en air-supply pipe is positioned coaxially therewith with the formation of an annular clearance between the outside surface of the tube and the inside surface of the housing. In the clearance there is provided a filtering member such as Kapron fibres placed into a rigid ring-shaped perforated cassette. The cassette height is less than the length of the air-supply pipe in the housing. In the direction of the air movement after the cassette an air-vent pipe is positioned which is directly connected to the inlet pipe of internal-combustion engines. The lower part of the housing which is its bottom is filled with an oil so that the outlet opening of the pipe is positioned above the level of the oil.
On the bottom of the housing coaxially with the pipe in the nulk of the oil a cup-like bath also filled with the oil is mounted. A jet of dusted air coming out of the air-supply pipe passes into the bath and displaces a layer of the oil therefrom by way of a dynamic head, and atomizes it. Drops of the atomized oil are intermixed with the air jet and wet the lower layers of the filtering member. The dusted air comes in contact with the oil which envelopes the dust particles and agglomerates them. Heavy particles of the dust with the excess of the oil get drained from the surface of the filtering member back into the lower part of the housing. The remaining dust particles with the air current penetrate into the lower oil-impregnated layers of the filtering member and get deposited on the fibres of the latter.
However, the dripping of the oil over the surface is non-uniform. In operation of an automobile or a tractor with such an air-cleaner under conditions of a rugged terrain there can take place inclinations of the air-cleaner which result in the situations where the oil excessively wets some regions of the filtering member and leaves other regions practically unwetted. The fibres of the filtering member only slightly wetted with the oil render a lower resistance to dust particle which, eventually, pass through the filtering member into the engine causing an early wear thereof. The excess of the oil from the abundantly wetted fibres also passsed into the engine with the dust, thus impairing its operation and causing wear too.
Also known is an air-clearer (FR, A 1536325) comprising a cylindrical housing, wherein substantially coaxially therewith an air-supply pipe is provided with the formation of a clearance between the outside surface of the tube and the inside surface of the housing and with a main filtering member positioned in said clearance. After the main filtering member along the direction of the air current an air-vent pipe is located communicating with the cavity of an internal-combustion engine and close to the lower end face of the housing on the side of the outlet opening of the pipe an additional filtering member is positioned. In the lower part of the housing between the end face and the additional filtering member oil is provided. The additional filtering member has a through opening coaxial with the air-supply pipe but with the size thereof considerably inferior to the air-supply pipe diameter.
In the engine operation a portion of the current of atmospheric air passing via the air-supply pipe penetrates into the through opening of the additional filtering member and, passing therethrough, contacts with the layer of an oil positioned under the additional filtering member in the lower part of the housing. The head of the dusted air is rather strong and pores of the additional filtering member constitute 1/2 of its volume, wherefore the oil drops pass through this filtering member and wet the air current passing right from the air-supply pipe into the main filtering member.
In such an air-cleaner upon the movement of a car or a tractor over a rugged terrain which is usual in their exploitation, the additional filtering member prevents an excessive spilling of the oil and reduces its ejection into the engine. However, a permanent change of the angle of inclination of the oil level to the air current outgoing from the pipe results in an insufficient and non-uniform spraying of the oil and, accordingly, a non-uniform wetting of the main filtering member, thus resulting in an increasing probability of penetration of dust particles into the engine, i.e. the efficiency of the air cleaning is lowered. Furthermore, at high angles of inclination or at a sharp change in the movement speed of a car or a tractor, running over some obstacles and the like, a portion of the oil is delivered through the additional filtering member into the main one, thus excessively saturating the latter with the oil which can be entrained, along with dust, and penetrates into the engine, which results in an invensive wear of the latter.
All these factors are detrimental to the dusting capacity of the air-cleaner which is determined by the amount of dust trapped by the filtering members. Besides, the presence of a considerable volume of the oil in the lower part of the housing entails a strictly vertical position of the air cleaner which is not always rational from the point of view of a compact arrangement thereof in the body of a car or a tractor.